This invention relates to palladium-nickel alloy plating soltuions, and in particular to palladium-nickel alloy solutions wherein palladium is added to the plating solution as tetramminepalladous chloride.
Palladium-nickel alloy plating solutions are generally disclosed in U.S. Pat. No. 3,580,820, issued on May 25, 1971 to Yamamura, et al. and assigned in part to the assignee of the subject application. The palladium-nickel alloy plating solutions of the Yamamura, et al. patent contain between about 5-30 g/l of palladium and 5-30 g/l of nickel. The source of the palladium is a monosalt, such as palladium chloride PdCl.sub.2 and a complex salt, such as palladous amino chloride Pd(NH.sub.3).sub.2 Cl.sub.2. Replenishment of the plating solutions is accomplished by adding the palladium salt directly to the bath together with additional ammonia water and dilute sulfuric acid to increase solubility. This tends to increase the volume of the plating solution. Additionally, these conventional plating solutions tend to generate an odor due to ammonia.
Accordingly, it would be desirable to provide an improved palladium-nickel alloy plating solution which does not present the problems associated with the prior art plating solutions.